[ RadSafe ] News from the American Heart Association Meeting

[ROY HERREN]

Public release date: 14-Nov-2010

Contact: American Heart Association Communications
214-706-1396
American Heart Association 

New protocol reduces children's radiation exposure during cardiac procedures
American Heart Association Meeting Report
A protocol that uses continuous real-time radiation monitoring, low-dose imaging 

programs and requires physician awareness of radiation dose, significantly 
reduced radiation exposure during electrophysiology procedures and catheter 
ablations to diagnose and treat heart arrhythmias in children, according to 
research presented at the American Heart Association's Scientific Sessions 2010. 


  
Invasive cardiac electrophysiology is used to diagnose and treat abnormal heart 
rhythms, or arrhythmias, which can range from the benign to the 
life-threatening. 

  
In the study, researchers looked at boys and girls at an average age of 14.5 
years who underwent electrophysiology procedures to diagnose and treat 
arrhythmias. In the procedures, doctors use fluoroscopy, which is a continuous 
X-ray, to visually guide catheters in the heart which are inserted through blood 

vessels in the groin or neck that lead to the heart. 

  
The downside of this imaging is that it exposes patients to a continuous flow of 

radiation, said Akash R. Patel, M.D., lead author of the study and an 
electrophysiology fellow in the Division of Cardiology at The Children's 
Hospital of Philadelphia in Pa. "Radiation exposure in pediatric 
electrophysiology procedures is not insignificant. We compared the radiation 
exposure of 70 children who had undergone the procedures before we began the 
protocol to that of 61 children who had the procedures after we instituted the 
protocol." 

  
The new protocol uses a low dose fluoroscopy setting and continuous real-time 
monitoring of radiation exposure. When the radiation dose registers at certain 
levels, the physician is notified so that the he or she can adjust the 
fluoroscopy cameras to minimize exposure.
 
The researchers found significantly reduced radiation exposure among children 
whose procedures were performed using the new protocol, including: 

    * 22 percent reduction in the time that the X-ray machine was on 
    * 52 percent reduction in the dose of X-ray entering the skin, which helps 
to 

prevent skin injury 

    * 51 percent reduction in median effective dose, which correlates with the 
lifetime increased risk of cancer from radiation exposure.
"While we did not measure what these lower doses mean in the long run, we 
presume, for example, that reducing the effective dose will decrease the child's 

lifetime increased cancer risk from radiation exposure," Patel said. 

"The public should be aware of radiation exposure from electrophysiology 
procedures, and physicians and hospitals should be vigilant in implementing 
protocols aimed at reducing radiation exposure from these procedures. This is 
especially important in children to minimize their risk of radiation-induced 
cancer because they should live for many decades after their procedures." 

  
Co-authors are: Jamie Ganley, B.S.; Xiaowei Zhu, M.S., Jonathan J. Rome, M.D.; 
Maully Shah, M.B.B.S.; and Andrew C. Glatz, M.D. Author disclosures are on the 
abstract. 

The Children's Hospital of Philadelphia funded the study. 
(Note: Actual presentation time is 9 a.m., CT, Monday, Nov. 15, 2010.)
Also Note These News Tips also for release at 11 a.m. CT, Sunday, Nov. 14, 2010:
 Abstract 11390/P1029 — Imaging teams' radiation exposure during percutaneous 
interventions higher than fluoroscopic operating teams 

  
Radiation exposure to imaging teams during percutaneous intervention for adult 
structural heart disease is higher than that of fluoroscopic operating teams — 
suggesting that imaging team members may need additional radiation protection 
measures. 

  
Percutaneous adult structural heart disease intervention is a family of invasive 

procedures that includes closing patent foramina ovalae, atrial septal defects, 
paravalvular leaks and transfemoral aortic valve implantations. It is currently 
a small but increasing part of cardiac interventional practice, researchers 
said. 

  
Such procedures often require fluoroscopic guidance by an operating team and 
ultrasonic guidance by an imaging team working together. This study was an 
observational study of ionizing radiation exposure to both operators and imagers 

during percutaneous interventions for adult structural heart disease. 

  
Fluoroscopic operating team members typically stand to the right of patients 
undergoing the procedures and imaging team members stand on the left. While all 
staff are required to wear protective lead aprons and thyroid collars, 
additional shielding is only provided for the operating team. 

  
Researchers examined how the radiation dose received by fluoroscopic operators 
differs from that received by the imaging team by measuring radiation exposure 
during percutaneous procedures for four months. They found greater radiation 
doses for those standing on the left of patients, which are the imaging 
personnel. 

  
This may have implications for both radiation protection and the use of 
noninvasive imaging during these procedures to reduce the reliance on X-ray 
technology, researchers said. 

  
Rodney De Palma, M.B.B.S, M.R.C.P.; University Hospital of Lausanne, Lausanne, 
Switzerland; Rodney.De-Palma at chuv.ch. 

(Note: Actual presentation time is 9 a.m., CT, Monday, Nov. 15, 2010.)
 Abstract 17486 — Radiation exposure from cardiac imaging after heart attack 
more likely to cause cancer in women than men 

Women who have had a heart attack, regardless of age, face a higher risk of 
cancer associated with exposure to low-dose ionizing radiation from heart 
imaging procedures than male heart attack patients. 

  
Researchers measured the effects of age and gender on low-dose ionizing 
radiation-associated risk of cancer in heart attack patients who had been 
exposed to the radiation from cardiac imaging procedures. Studying a database of 

56,606 male and 26,255 female heart attack patients between 1996 and 2006 in 
Quebec, they found: 

    * For women, the median age was 71.7 years, low-dose ionizing radiation 
exposure was 3.7 millisieverts (mSv) per year, and 3,545 new cancers were 
observed over 4.2 years. 

    * For men, the median was 59.7 years, low-dose ionizing radiation exposure 
was 

4.1 mSv/year, and 8,475 new cancers were observed over 4.8 years. 

    * The interaction between gender and low-dose ionizing radiation was 
significant, but it wasn't between age and low-dose ionizing radiation. 

    * For every 10 mSv increase in low-dose ionizing radiation, the risk of 
cancer 

increased by 4.4 percent in womem and 2.1 percent in men.
Jonathan Afilalo, M.D., M.Sc.; Division of Cardiology, SMBD-Jewish General 
Hospital/McGill University, Montreal, Quebec, Canada; (687) 935-4619; 
jonathan at afilalo.com. 

(Note: Actual presentation time is 9 a.m., CT, Tuesday, Nov. 16, 2010.)
Author disclosures are on the abstracts.
###
Statements and conclusions of study authors that are presented at American Heart 

Association scientific meetings are solely those of the study authors and do not 

necessarily reflect association policy or position. The association makes no 
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strict policies to prevent these relationships from influencing the science 
content. Revenues from pharmaceutical and device corporations are available at 
www.heart.org/corporatefunding. 

NR10-1139 (SS10/Patel)
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